Pass 'needs_swap' as a parameter to SHIFT_BYTES.

It feels wrong to have it as an implicit parameter sucked in via the textual
expansion of the macro. Whilst it can be derived from the parameter
'datumtype', it seems that the C compiler generates a lot less efficient code
that way.

diff --git a/pp_pack.c b/pp_pack.c
index 8c5c76e..23d8db9 100644 (file)
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -146,7 +146,7 @@ typedef union {
 #endif
 
 /* Only to be used inside a loop (see the break) */
-#define SHIFT_BYTES(utf8, s, strend, buf, len, datumtype)      \
+#define SHIFT_BYTES(utf8, s, strend, buf, len, datumtype, needs_swap)  \
 STMT_START {                                           \
     if (utf8) {                                                \
         if (!uni_to_bytes(aTHX_ &s, strend,            \
@@ -160,14 +160,14 @@ STMT_START {                                              \
     }                                                  \
 } STMT_END
 
-#define SHIFT16(utf8, s, strend, p, datumtype)                          \
-       SHIFT_BYTES(utf8, s, strend, OFF16(p), SIZE16, datumtype)
+#define SHIFT16(utf8, s, strend, p, datumtype, needs_swap)              \
+       SHIFT_BYTES(utf8, s, strend, OFF16(p), SIZE16, datumtype, needs_swap)
 
-#define SHIFT32(utf8, s, strend, p, datumtype)                          \
-       SHIFT_BYTES(utf8, s, strend, OFF32(p), SIZE32, datumtype)
+#define SHIFT32(utf8, s, strend, p, datumtype, needs_swap)              \
+       SHIFT_BYTES(utf8, s, strend, OFF32(p), SIZE32, datumtype, needs_swap)
 
-#define SHIFT_VAR(utf8, s, strend, var, datumtype)     \
-       SHIFT_BYTES(utf8, s, strend, &(var), sizeof(var), datumtype)
+#define SHIFT_VAR(utf8, s, strend, var, datumtype, needs_swap)          \
+       SHIFT_BYTES(utf8, s, strend, &(var), sizeof(var), datumtype, needs_swap)
 
 #define PUSH_VAR(utf8, aptr, var)      \
        PUSH_BYTES(utf8, aptr, &(var), sizeof(var))
@@ -1338,7 +1338,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if SHORTSIZE != SIZE16
            while (len-- > 0) {
                short ashort;
-               SHIFT_VAR(utf8, s, strend, ashort, datumtype);
+                SHIFT_VAR(utf8, s, strend, ashort, datumtype, needs_swap);
                if (!checksum)
                    mPUSHi(ashort);
                else if (checksum > bits_in_uv)
@@ -1357,7 +1357,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if U16SIZE > SIZE16
                ai16 = 0;
 #endif
-               SHIFT16(utf8, s, strend, &ai16, datumtype);
+                SHIFT16(utf8, s, strend, &ai16, datumtype, needs_swap);
 #if U16SIZE > SIZE16
                if (ai16 > 32767)
                    ai16 -= 65536;
@@ -1374,7 +1374,8 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if SHORTSIZE != SIZE16
            while (len-- > 0) {
                unsigned short aushort;
-               SHIFT_VAR(utf8, s, strend, aushort, datumtype);
+                SHIFT_VAR(utf8, s, strend, aushort, datumtype, needs_swap,
+                          needs_swap);
                if (!checksum)
                    mPUSHu(aushort);
                else if (checksum > bits_in_uv)
@@ -1394,7 +1395,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if U16SIZE > SIZE16
                au16 = 0;
 #endif
-               SHIFT16(utf8, s, strend, &au16, datumtype);
+                SHIFT16(utf8, s, strend, &au16, datumtype, needs_swap);
                if (datumtype == 'n')
                    au16 = PerlSock_ntohs(au16);
                if (datumtype == 'v')
@@ -1414,7 +1415,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 # if U16SIZE > SIZE16
                ai16 = 0;
 # endif
-               SHIFT16(utf8, s, strend, &ai16, datumtype);
+                SHIFT16(utf8, s, strend, &ai16, datumtype, needs_swap);
                 /* There should never be any byte-swapping here.  */
                 assert(!TYPE_ENDIANNESS(datumtype));
                if (datumtype == ('n' | TYPE_IS_SHRIEKING))
@@ -1433,7 +1434,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'i' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                int aint;
-               SHIFT_VAR(utf8, s, strend, aint, datumtype);
+                SHIFT_VAR(utf8, s, strend, aint, datumtype, needs_swap);
                if (!checksum)
                    mPUSHi(aint);
                else if (checksum > bits_in_uv)
@@ -1446,7 +1447,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'I' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                unsigned int auint;
-               SHIFT_VAR(utf8, s, strend, auint, datumtype);
+                SHIFT_VAR(utf8, s, strend, auint, datumtype, needs_swap);
                if (!checksum)
                    mPUSHu(auint);
                else if (checksum > bits_in_uv)
@@ -1458,7 +1459,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'j':
            while (len-- > 0) {
                IV aiv;
-               SHIFT_VAR(utf8, s, strend, aiv, datumtype);
+                SHIFT_VAR(utf8, s, strend, aiv, datumtype, needs_swap);
                if (!checksum)
                    mPUSHi(aiv);
                else if (checksum > bits_in_uv)
@@ -1470,7 +1471,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'J':
            while (len-- > 0) {
                UV auv;
-               SHIFT_VAR(utf8, s, strend, auv, datumtype);
+                SHIFT_VAR(utf8, s, strend, auv, datumtype, needs_swap);
                if (!checksum)
                    mPUSHu(auv);
                else if (checksum > bits_in_uv)
@@ -1483,7 +1484,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if LONGSIZE != SIZE32
            while (len-- > 0) {
                long along;
-               SHIFT_VAR(utf8, s, strend, along, datumtype);
+                SHIFT_VAR(utf8, s, strend, along, datumtype, needs_swap);
                if (!checksum)
                    mPUSHi(along);
                else if (checksum > bits_in_uv)
@@ -1501,7 +1502,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if U32SIZE > SIZE32
                ai32 = 0;
 #endif
-               SHIFT32(utf8, s, strend, &ai32, datumtype);
+                SHIFT32(utf8, s, strend, &ai32, datumtype, needs_swap);
 #if U32SIZE > SIZE32
                if (ai32 > 2147483647) ai32 -= 4294967296;
 #endif
@@ -1517,7 +1518,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if LONGSIZE != SIZE32
            while (len-- > 0) {
                unsigned long aulong;
-               SHIFT_VAR(utf8, s, strend, aulong, datumtype);
+                SHIFT_VAR(utf8, s, strend, aulong, datumtype, needs_swap);
                if (!checksum)
                    mPUSHu(aulong);
                else if (checksum > bits_in_uv)
@@ -1537,7 +1538,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if U32SIZE > SIZE32
                au32 = 0;
 #endif
-               SHIFT32(utf8, s, strend, &au32, datumtype);
+                SHIFT32(utf8, s, strend, &au32, datumtype, needs_swap);
                if (datumtype == 'N')
                    au32 = PerlSock_ntohl(au32);
                if (datumtype == 'V')
@@ -1557,7 +1558,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 #if U32SIZE > SIZE32
                ai32 = 0;
 #endif
-               SHIFT32(utf8, s, strend, &ai32, datumtype);
+                SHIFT32(utf8, s, strend, &ai32, datumtype, needs_swap);
                 /* There should never be any byte swapping here.  */
                 assert(!TYPE_ENDIANNESS(datumtype));
                if (datumtype == ('N' | TYPE_IS_SHRIEKING))
@@ -1575,7 +1576,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'p':
            while (len-- > 0) {
                const char *aptr;
-               SHIFT_VAR(utf8, s, strend, aptr, datumtype);
+                SHIFT_VAR(utf8, s, strend, aptr, datumtype, needs_swap);
                /* newSVpv generates undef if aptr is NULL */
                mPUSHs(newSVpv(aptr, 0));
            }
@@ -1628,7 +1629,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
            EXTEND(SP, 1);
            if (s + sizeof(char*) <= strend) {
                char *aptr;
-               SHIFT_VAR(utf8, s, strend, aptr, datumtype);
+                SHIFT_VAR(utf8, s, strend, aptr, datumtype, needs_swap);
                /* newSVpvn generates undef if aptr is NULL */
                PUSHs(newSVpvn_flags(aptr, len, SVs_TEMP));
            }
@@ -1637,7 +1638,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'q':
            while (len-- > 0) {
                Quad_t aquad;
-               SHIFT_VAR(utf8, s, strend, aquad, datumtype);
+                SHIFT_VAR(utf8, s, strend, aquad, datumtype, needs_swap);
                if (!checksum)
                     mPUSHs(aquad >= IV_MIN && aquad <= IV_MAX ?
                           newSViv((IV)aquad) : newSVnv((NV)aquad));
@@ -1650,7 +1651,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'Q':
            while (len-- > 0) {
                Uquad_t auquad;
-               SHIFT_VAR(utf8, s, strend, auquad, datumtype);
+                SHIFT_VAR(utf8, s, strend, auquad, datumtype, needs_swap);
                if (!checksum)
                    mPUSHs(auquad <= UV_MAX ?
                           newSVuv((UV)auquad) : newSVnv((NV)auquad));
@@ -1665,7 +1666,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'f':
            while (len-- > 0) {
                float afloat;
-               SHIFT_VAR(utf8, s, strend, afloat, datumtype);
+                SHIFT_VAR(utf8, s, strend, afloat, datumtype, needs_swap);
                if (!checksum)
                    mPUSHn(afloat);
                else
@@ -1675,7 +1676,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'd':
            while (len-- > 0) {
                double adouble;
-               SHIFT_VAR(utf8, s, strend, adouble, datumtype);
+                SHIFT_VAR(utf8, s, strend, adouble, datumtype, needs_swap);
                if (!checksum)
                    mPUSHn(adouble);
                else
@@ -1685,7 +1686,8 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'F':
            while (len-- > 0) {
                NV_bytes anv;
-               SHIFT_BYTES(utf8, s, strend, anv.bytes, sizeof(anv.bytes), datumtype);
+                SHIFT_BYTES(utf8, s, strend, anv.bytes, sizeof(anv.bytes),
+                            datumtype, needs_swap);
                if (!checksum)
                    mPUSHn(anv.nv);
                else
@@ -1696,7 +1698,8 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
        case 'D':
            while (len-- > 0) {
                ld_bytes aldouble;
-               SHIFT_BYTES(utf8, s, strend, aldouble.bytes, sizeof(aldouble.bytes), datumtype);
+                SHIFT_BYTES(utf8, s, strend, aldouble.bytes,
+                            sizeof(aldouble.bytes), datumtype, needs_swap);
                if (!checksum)
                    mPUSHn(aldouble.ld);
                else